A method for regulating web tension is disclosed in EP 0 837 825 B1. In addition to the measured actual values of the web tension, further values defining the machine status, and defining method-related properties are employed for the regulation. Besides the actually measured tension values, predeterminable web-specific parameters are also included in the regulating algorithm.
DE 198 34 725 A1 shows, inter alia, a method for regulating a web tension. Actual web tension values upstream and/or downstream of the printing unit are entered into a regulating device, which regulates the web tension at the draw-in device in such a way that, in spite of interference values such as, for example, a varying module of elasticity of the web, the web tension is maintained within a range which is optimal for the inking and cutting registrations.
The object of DE 197 54 878 A1 is to provide a winding tightness on a roll as constant, or as pre-definable, as possible.
For obtaining a uniform wind-up roll curve, values measured by the unwinding roll curve are used for affecting the forces in accordance with the desired paper winding characteristic reference variable, such as winding tightness. Then, the measured values are used together with the empirical values.
A method and a device of a pre-printed web is known from DE 19 66,795 A1. In connection with a roll change a web tension is reduced at least temporarily, for example for assuring a correct alignment of the lines in the renewed printing of the web.